Switch and signal control system for railroads



Feb. 10, 1942. A. LANGDQN ET AL 2,272,565

SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS Filed Aug. 24, 1939 3 Sheets-Sheet l AGE @SML F|e..1.A.

Ayang don and wLLivingsTdn THEIR ATTORNEY INVENTORS Feb. 10, 1942'. A. LANGDON ETAI. 2,272,565

SYSTEM FOR RAILROADS- SWITCH AND SIGNAL CONI ROL Filed Aug. 24, 1939 3 Sheets-Sheet 2 a INVENTORS gsTon m .m .w my WW MM 0 n W L A Feb. 10, 1942. A. LANGDON ETAL 2,272,565

SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS Filed Aug. 24 1939 3 Sheets-Sheet 3 INVENTOR5 TH EI'R ATTORNEY A.La.n

Patented Feb. 10, 1942 TENT OE'EIQE SWITCH AND SIGNAL CONTROL SYSTEM FOR RAILROADS Application August 24, 1939, Serial No. 291,716

8 Claims.

This invention relates to switch and signal control systems for railroads, and it more partieularly pertains to such systems of the entranceexit type for governing the establishment of routes in a track layout remotely located from a control machine.

In a switch and signal control system of the entrance-exit type a control machine in a control ofiice is provided with a control panel upon which is constructed a miniature track diagram of the track layout for which the system is provided. An operator can cause the establishment of any desired route through the track layout by actuation of buttons or other suitable contactors disposed on the miniature track diagram at points corresponding to the entrance and exit ends of such route. The route ends are defined by the location of the signals at the track layout, each route being generally considered as extending from a signal at an entrance point to another signal for governing traflic in the same direction, or to an arbitrary point, as an exit point.

An object of the present invention is to provide an entrance-exit type of system in which a route establishing means is provided at a remote track layout having an entrance and exit relay for each respective entrance and exit point which is governed by direct wire control over a line circuit by the respective entrance or exit button on the panel of the control machine at the control ofiice.

Another object of the present invention is to cause each entrance relay controlled over a single line circuit extending to the control ofiice, to respond distinctively to each of a plurality of several different controls that can be designated by an operator at the control oiiice by the actuation of the entrance button for that entrance point. Such distinctive controls are, namely, the designation of an entrance point for a route governed by a stick signal by the depression of the entrance button for such point, the designation for restoration for an entrance point thus designated by the pulling out of the entrance button, the designation of an entrance point for a route governed by a non-stick signal, by the rotation of the entrance button from its normal position, and the designation for restoration for an entrance point thus designated by the rotation of the entrance button. from its operating position by rotation to its normal position with respect to rotation. The establishment of a route having its entrance end designated by the depression of the entrance button for that entrance point is effective dependent upon the 55 condition of occupancy of such route, but the establishment of a route having its entrance end designated by the rotation of the entrance button for that entrance point is effective independent of the condition of occupancy of such route. It is to be understood that other means for distinctively designating the different controls can as Well be employed and that the specific controls designated for each entrance point and transmitted by direct wire control to the remote track layout can vary in accordance with the requirements of practice.

Another object of the present invention is to provide that a direct wire single line circuit is used for governing the picking up of each exit relay and that the same line circuit is used in transmitting back to the control office an indication concerning the condition of the signal at that exit point. 1

In accordance with the energization of entrance and exit relays at the track layout a route can be selected and established by a number of different route establishing means of the general classsuch, for example, as the self-selecting network system shown in the patent to A. Langdon, Patent No. 2,148,865, dated February 28, 1939.

Other objects, purposes and characteristic features of the present invention will be in part obvious from the accompanying drawings, and in part pointed out as the description of the invention progresses.

In describing the invention in detail, reference is made to the accompanying drawings, in which corresponding parts are, designated by corresponding reference characters, in which those parts having similar features and functions are designated by like letter reference characters which are generally made distinctive either by reason of precedingnumerals, or by preceding letter reference characters characteristic of the signal locations with which such parts are associated, and in which:

Fig. 1A and Figs. 1B and 1C, placed one above the other to the right .of Fig. 1A, illustrate one embodiment of the present invention whereby an entrance-exit system is provided for the control of the switches and signals at a track layout remotely located from a control machine at a control ofiice.

' In order to simplify the description, reference is made from time to time to functions characteristic of a particular group of relays or devices by use of letter reference characters common to such devices without their preceding numerals or letters representative of the signals for which such devices are provided. It is to be understood that such reference applies in general to any of the parts designated in the drawings by letter reference characters which are similar except for preceding numerals or letters representative of signal locations.

The various devices and circuits constituting the embodiment of the present invention have been shown diagrammatically and certain conventional illustrations have been employed for the purpose of simplifying the illustration thereof and facilitating the disclosure as to principles involved rather than for the purpose of illustrating the specific construction and arrangement of parts that would be employed in practice. Thus, conventional symbols are used for illustration of the various devices and relay contacts, and symbols are used to indicate connections to terminals of batteries or other sources of electric current instead of showing all of the wiring connections to those terminals.

The symbols and are employed to indicate the positive and negative terminals respectively of suitable batteries or other sources of direct current, and the circuits with which those symbols are used always have current flowing in the same direction. The symbols (13+) and (13-) indicate connections to the opposite terminals of a suitable battery or other direct current sourc which has a central or intermediate tap designated by (UN) and the circuits with which those symbols are used can have current flowing in one direction or the other, dependent upon the particular terminal used in combination with the intermediate terminal (CN).

The symbols (B+) and (B-) shown associated with apparatus at the control ofiice are opposite terminals of a control office battery, and the symbols (3+) and (B-) shown associated with apparatus at the field are opposite terminals of a battery located in the field. A common wire (not shown) extends from the (CN) terminal of the control oifice battery to the (CN) terminal of the field battery. If alternating current is to be used in place of direct current, the particular symbols employed represent the relative instantaneous polarities.

Track Zayut.-Vlith reference to Fig. 1B, a simple track layout is illustrated for this embodiment of the present invention in which a through track has a second track connected thereto by a track switch TS. Although only a simple track layout is shown in this embodiment of the present invention it is to be understood that the present invention can as well be applied to any track layout encountered in practice in accordance with the general principles relative to the system as hereinafter set forth.

Signals are provided for governing trafiic over the track switch TS in both directions, signals A and B being provided for governing east bound trafiic to th right and signal C being provided for governing west bound traflic to the left. The signals illustrated are of the color light type having individual color lamp units, the upper unit providing a green clear indication, and the lower unit providing a red danger indication. An additional low speed indication is provided for signal B under certain conditions by the flashing of the green lamp in that signal. It is to be understood that different signal indications can as well be provided, and that an additional yellow caution indication can be provided in accordance with the requirements of practice. It is also to be understood that other types of signals such as semaphore and search light signals could as well be used.

The track switch TS is power operated by a suitable switch machine which can be of the type shown, for example, in the patent to W. K. Howe, Patent No. 1,466,903, dated September 4, 1923, and the motor of the switch machine can have over-load protection and other features commonly employed in the control of switch machine motors provided in a suitable manner such as that shown in the patent to W. H. Hoppe et al., Patent No. 1,877,876, dated September 20, 1932.

Associated with the track switch TS is a polar neutral relay WP provided for repeating the locked position of the track switch in correspondence with the locked position of the switch machine SM. The relay WP is controlled in accordance with the usual practice to provide that it is energized with one polarity when the track switch and the switch machine are locked in a normal position, and is energized with the opposite polarity when the switch machine and track switch are in a reverse locked position. Relay WP is deenergized when the track switch TS and/or the switch machine SM are unlocked.

Track circuits are provided throughout the track layout in the usual manner, and fouling protection is provided for the track switch TS. Track relay TR is provided for the detector track section T, and a track relay 2TB. is provided for the track section 2T, both track relays being normally energized by track circuits of the usual type.

Control ojfice devices.-A principal part of the control machine in the control office is the con trol panel upon which is constructed a miniature track diagram (see Fig. 1A) corresponding with the remote track layout in the field for which the machine is provided. Disposed on the track diagram are entrance and exit buttons NE and KB respectively at positions corresponding to the respective entrance and exit points for which such buttons are provided. The entrance buttons NB are of the push-pull and rotary type being biased in a normal position with respect to push and pull operation, and having an operating position when rotated from its normal position in which it remains until manually restored to its normal position with respect to rotation. A suitable means for the construction of such a control button is shown in th prior application of J. F. Merkel, Ser. No. 158,720, filed August 12, 1937. Each of the exit buttons X8 is of the self-restoring push button type having a contact closed when such button is in a depressed position.

Suitable indicator lamps are provided along the miniature track diagram to keep an operator well informed as to the condition of occupancy of the various track sections at the field station, the condition of the signals, and the routes established through the track layout. A coder CD is also provided at the control ofiice for providing pulsating energy required for the flashing of certain of the indicator lamps under certain conditions.

As an auxiliary control means an auxiliary control lever SML is provided on the control panel for each track switch.

Field devices.An entrance relay of the polar neutral type is provided for each entrance point at the track layout (see Fig. 1B), and such entrance relay is picked up upon designation of that entrance point at the control office and maintained energized dependent for restoration upon passage of a train or manual designation for restoration to normal.

An exit repeater relay XP is provided at the track layout for each exit point, and such relay is responsive to the depression of the correspond-' ing exit button XB at the control office. Each exit repeater relay XP is energized only during the time when the corresponding button XB is in a depressed position.

An exit relay XR is picked up at the track layout when the relay XP for that exit point is picked up, if an entrance point has previously been designated for an available route extending to that exit point, and the energization of an exit relay XR causes the establishment of a stick circuit to maintain such relay energized dependent upon restoration of the entrance relay NR for the entrance end of that route.

Associated with the establishment of each desired route in accordance with an entrance relay NR and an exit relay XR picked up for the respective entrance and exit ends of such route, are relays'N, R, WZZ, L, LS, NCR, RCR and G provided for purposes substantially as set forth for relays designated by similar reference characters in the above mentioned patent to A. Langdon, Patent No. 2,148,865, dated February 28, 1939.

A relay WZ is provided at the track layout for each track switch for repeating the position of the corresponding auxiliary lever SML at the control ofiice, and a track circuit repeater relay BI-IR is provided at the track layout for repeating the track sections included in braking distance in advance of signal B. A coder CD is provided for the purpose of supplying pulsating Having thus described the apparatus used in this embodiment of the present invention, consideration will now be given to the functions of such apparatus under various typical operating conditions.

Operation Inasmuch as the route establishing means in the field responsive to the contemporaneous energization of entrance and exit relays is comparable to the route establishing means disclosed in the patent to A. Langdon, Patent No. 2,148,865, dated February 28, 1939, and in the application of Wight and Langdon, Ser. No. 245,384, filed December 13, 1938, now U. S. Patent 2,219,502, granted Oct. 29, 1940, it is believed unnecessary to show and describe in detail in this disclosure all of the features of the self-selecting network for the establishment of routes, as reference can be made to those disclosures for details not herein shown and described.

The conditions assumed to be normal are those illustrated in which all of the relays are normally deenergized with the exception of the track relays TR and 2TB, relay BHR, lock relays L and LS, route locking relays ES and WS, relay WP, and the correspondence relay NCR. The correspondence relay NCR is illustrated as normally energized because it has been assumed that the last route established through the track layout was a through route on the main track to require the position of the track switch TS to be normal.

Under normal conditions the relay BER is energized by a circuit closed from including front contact [0 of relay 2TR (see Fig. 1B) front contact H of relay TR, and winding of relay BHR, to Relay L is normally energized by a circuit closed from including front contact l2 of relay L, front contact I3 of relay TR, front contact 14 of relay WS, front contact I 5 of relay ES, and winding of relay L, to Relay LS is normally energized by a circuit closed from including front contact [6 of relay L,

back contact I! of relay WZZ, and winding of relay LS, to Relay NCR (see Fig. 1C) is normally energized by a circuit closed from including back contact l8 of relay R, winding of relay NCR, polar contact IQ of relay ZWP in a right hand position, and front contact 20 of relay 2W1, to The relays ES and WS, which are respectively east and west directional stick route locking relays for the track section T are normally energized in accordance with circuits (not shown) provided similar to circuits for corresponding relays shown in the above mentioned patent to A. Langdon, Patent No. 2,148,865.

The control circuits provide that the east or west (dependent upon the direction of traffic) stick relays are dropped away for the track sections included in a route established as soon as the signal governing entrance to that route is cleared, and such relays are picked up again after a train has passed through their respective track sections. If it is required in practice that approach locking be provided in addition to the route locking, such approach locking can be included in the control circuits of the east and west stick relays ES and WS in accordance with circuits shown for relays designated by similar nomenclature in the patent to C. F. Stoltz, Patent No. 2,115,511, dated April 26, 1938.

If, under normal conditions, an operator designating an entrance point by the depression of an entrance button, the corresponding entrance relay NR is picked up with its polar contacts operated to a right hand position, and the picking up of that relay under such conditions closes a stick circuit including the upper winding of that relay to cause such relay to remain energized until a train passes the corresponding entrance point upon accepting the entering signal to the route to be established. In other words, the depression of an entrance button causes the energization of the entrance relay NR for that entrance point with such a polarity as to cause the establishment of a stick circuit for such entrance relay dependent for deenergization upon passage of a train.

If, however, an operator designates an entrance point by the rotation of an entrance button NB to an operating position rather than by the depression of such button, the corresponding entrance relay NR is energized with a polarity to operate its polar contacts to a left hand position and thus prevent the closing of a stick circuit for its upper winding. Such energization obviously causes a relay NR to remain energized as long as an operator leaves the entrance button NB in an operating position by rotation, and it is restored to norfor the designation of an entrance point at signal B at a time when the normal conditions of the system exist as they have been described. Relay BNR is picked up upon the depression of button BNB under such conditions by the energization of a circuit closed from (13+) including contact 2| of button BNB (see Fig. 1A) closed in a depressed position, rotary contact 22 of button BNB in a normal position with respect to rotation, wire 23, lower winding of relay BNR (see Fig. 1B), polar contact 24 of relay BNR in a right hand position, and front contact 25 of relay TR, to (ON). The picking up of relay BNR due to the energization of that circuit causes the establishment of a stick circuit for that relay from including front contact 26 of relay TR, front contact 21 of relay BNR, polar contact 28 of relay BNR in a right hand position, and upper winding of relay BNR, to

Contact 22 of button BNB is included in the circuit to check that the button is in a normal position with respect to rotation before the de pression or pulling out of the button can become effective for governing the entrance relay NR for the corresponding entrance point. If such check is accomplished mechanically in the structure of the button, as shown, for example, in the application of J. F. Merkel, Ser. No. 158,720, filed August 12, 1937, contact 22 of button BNB is not required in the control circuits for relay BNR.

If an operator rotates the button BNB (see Fig. 1A) in a clockwise direction at a time when the normal conditions exist as they have been described, relay BNR. (see Fig. 1B) has its polar contacts shifted in position by the momentary energization of a circuit having the opposite polarity to the circuit described above which can be traced from (B-), including contact 29 of button BNB in a clockwise rotated position, wire 23, lower winding of relay BNR, polar contact 24 of relay BNR in a right hand position, and front contact 25 of relay TR, to (CN). Such energization causes the polar contacts of relay BNR to shift to a left hand position and thus close a pickup circuit for relay BNR from (B), including contact 29 of button BNB in a clockwise rotated position, wire 23, lower winding of relay BNR, and polar contact 2 of relay BNR in a left hand position, to (CN). The picking up of relay BNR due to the energization of that circuit provides that relay BNR is dependent upon energy selected at the control office by button BNB for its energization as the stick circuit for that relay is open at polar contact 28 of relay BNR in a right hand position.

It is provided that the relay BNR cannot ordinarily be picked up if track section T is occupied by a train because the pick-up circuit for relay BNR in accordance with the depression of button BNB is open at front contact of relay TR. However, if an operator desires to set up a route for a following train from signal B to signal C when the preceding train is occupying track section T, he can cause the picking up of relay BNR for defining the entrance end of that route by rotating button BNB in a clockwise direction from its normal position. Thus, in view of the fact that the normal mode of operation on the part of an operator for the establishment of routes is to depress the entrance buttons, a special extraordinary mode of operation must be followed by the rotation of an entrance button in order to set up a route including that entrance point if the track section immediately in advance of the entering signal is occupied by a train.

To consider specifically the circuit which can cause the energization of relay BNR when the track section T is occupied assume that an operator rotates the button BNB to a clockwise operating position at a time when such conditions exist. Under such conditions relay BNR has its polar contacts operated to a left hand position by the momentary energization of a circuit closed from (13-), including contact 29 of button BNB in a clockwise rotated position, wire 23, lower winding of relay BNR, polar contact 24 of relay BNR in a right hand position, and back contact 25 of relay TR, to (B+). Such circuit is only momentarily closed because the polar contact 24 of relay BNR is immediately operated to a left hand position in accordance with the polarity by which the lower winding of relay BNR is energized, and the operation of polar contact 24 to that position causes the picking up of relay BNR by the energization of a circuit which has already been described.

If an operator designates an exit point in the establishment of a desired route, such designation causes the picking up in the field of an exit repeater relay XP for that particular exit point. As a typical example of the circuit provided for each XR relay, assuming the exit button BXIB (see Fig. 1A) to be depressed for the designation of an exit point, a circuit is energized for the picking up of relay BXP from (B+), including contact 36 of button BXB closed in a depressed position, wire 3|, back contact 32 of relay BG, back contact 33 of relay BNR, and winding of relay EXP, to (CN). The picking up of such relay causes the picking up of the relay BXR if an entrance point for an available route having that point as exit has been designated.

Having thus described the means by which the entrance and exit controls designated at the control office are defined in the field by the energize.- tion of entrance and exit relays, consideration will now be given to specific examples of how a route is completely established, although it is to be understood that reference is to be made to the above mentioned patent to A. Langdon, Patent No. 2,148,865, for a more detailed description of the route establishing means provided.

As a typical example of how a route can be established assume that an operator designates an entrance point at signal A and an exit point at signal C when the normal conditions of the system exist as they have been described. The designation of the entrance point causes the picking up of relay ANR by the energization of circuits similar to those which have been described for the energization of relay BNR in accordance with the actuation of the entrance button BNB. When the exit point is designated at signal C by the depression of button CXB, the relay CXP is picked up by the energization of a circuit similar to the circuit described for the energization of relay BE, and the picking up of relay CXP subsequent to the picking up of the entrance relay ANR causes the picking up of relay CXR by the energization of a circuit closed from including front contact 36 of relay ANR (see Fig. 1C) back contact 35 of relay AXR, back contact 36 of relay N, back contact 3'! of relay Y, winding of relay CXR, and front contact 38 of relay CXP, to The picking up of relay CXR closes a stick circuit for that relay at front contact 39 to shunt front contact 38 of relay CXP out of the circuit just described.

When relay CXR is picked up, relay R is picked up (because the preselecting relay Y is in a dropped away position) by the energization of a circuit closed from including front contact 40 of relay CXR,back contact 4| of relay Y, upper winding of relay R, and back contact 42 of relay N, to The picking up of relay R causes the dropping away of the normal correspondence relay NCR by opening the circuit for that relay at back contact I8, and the dropping away of that relay closes a stick circuit for the lock relay LS, from including front contact I6 of relay L, back contact 43 of relay RCR, back contact 44 of relay NCR, front contact 45 of relay LS, winding of relay LS, to The picking up of relay R also causes the picking up of relay WZZ by the energization of a circuit closed from including front contact lb of relay L, front contact 46 of relay R, and lower winding of relay WZZ, to When relay WZZ is picked up the closing of its front contacts 41 and 48 causes the operation of the switch machine SM to a reverse position to correspond with the position required for the route to be established.

After the track switch has completed its operation to a reverse locked position in correspondence with the switch machine SM, the correspondence relay RCR is picked up by the energization of a circuit closed from including back contact 93 of relay N, winding of relay RCR, polar contact I9 of relay WP in a left hand position, and front contact 20 of relay WP, to Upon the picking up of relay RCR, relay LS is dropped away by the opening of the stick circuit for that relay at back contact 43, and the dropping away of that relay removes energy from the control wires extending to the switch machine and also closes the circuit for signal control relay AG from including front contact 94 of relay CXR, back contact 49 of relay LS, front contact 50 of relay RCR, back contact 51 of relay NCR, back contact 52 of relay AXR, front contact 53 of relay ANR, and winding of relay AG, to The opening of back contact 54 of relay AG causes the red lamp in signal A to be extinguished and the closing of front contact 54 causes the green lamp in signal A to be illuminated.

The clearing of signal A causes the dropping away of the route locking relay ES to open the circuit for relay L at front contact l5, and the dropping away of relay L closes a stick circuit for the energization of the center winding of relay R from including back contact 55 of relay L, front contact 56 of relay R, center winding of relay R, and back contact 42 of relay N, to Such stick circuit is provided in order that the relay R is maintained energized after a train enters the route established for the purpose of preventing the preconditioning of a route not available in accordance with the principles set forthin the above mentioned patent to A. Langdon, Patent No. 2,148,865.

If a train approaching signal A accepts that signal, and if relay ANR has been picked up in the defining of that entrance point by the depression of the button ANB at the control office, the dropping away of the track relay TR for the detector track section T causes the dropping away of the entrance relay ANR by the opening of the stick circuit for that relay at front contact 2%, and relay ANR in dropping away causes the release of relay CXR because of the opening of the stick circuit for that relay at front contact 34. The dropping away of relay CXR opens the pick-up circuit for relay R at front contact 45, but relay R is maintained energized because of its stick circuit until the passing train has left track section T to cause the picking up of the route locking relay ES and the track relay TR. At such time the relay L is picked up by the energization of a circuit closed from including back contact 5'! of relay WZ, front contact I 3 of relay TR, front contact I 4 of relay WS, front contact l 5 of relay ES, and winding of relay L, to The energization of that relay causes the establishment of the stick circuit for that relay which has been heretofore described when considering the normal conditions of the system.

The picking up of relay L causes relay R to be dropped away by opening the stick circuit for that relay at back contact 55, and also causes the picking up of relay LS by the energization of a circuit which has already been described, thus completing the restoration of the route establishing means associated with the route assumed to have been set up to its normal conditions.

Should an operator have designated the entrance point for the route set up as previously described from signal A to signal C by the rotation of the button ANB to a clockwise operating position, the route would obviously be maintained established as long as the operated position of the button ANB is maintained in an operating position. Upon restoration of that button to normal relay ANR would be dropped away because of the opening of its circuit at contact 15 (see Fig. 1A) of button ANB, and the restoration of the route establishing means in accordance with the dropping away of relay ANR would become effective in a manner similar to that which has been described.

Assuming a route to have been established and passage of a train to have been eifected as has just been described from signal A to signal C, the track switch TS and the switch machine SM are left in a reverse locked position with the relay RCR in a picked up position. When such conditions exist, to consider a specific example of how a route can be established requiring the track switch to be operated to a normal position, as-

sume that an operator designates an entrance point at signal B by the depression of the button BNB and thus causes the picking up of the entrance relay BNR with its polar contacts operated to a right hand position. The designation of an entrance point at signal B and the picking up of relay BNR causes the picking up of relay Y (see Fig. 1C) by the energization of a circuit closed from including front contact 58 of relafBNR, back contact 59 of relay BXR, back contact 6i] of relay R, and winding of relay Y, to The designation of an exit point at signal C for a route having its entrance point at signal B by the depression of button CXB, subsequent to the picking up of relays BNR and Y, causes the picking up of relay CXR. by the energization of a circuit closed from including front contact 58 of relay BNR, back contact 59 of relay BXR, back contact of relay R, front contact 31 of relay Y, winding of relay CXR, and front contact 38 of relay 029?, to The picking up of relay CXR closes a stick circuit at front contact 39 to shunt contact 38 of relay CXP out of the circuit just described.

The picking up of relay CXR, with relay Y in a picked up position, causes the picking up of relay N by the energization of a circuit closed from including front contact 40 of relay CXR, front contact 4| of relay Y, upper winding of relay N, and back contact 6! of relay R, to Upon the picking up of relay N, relay WZZ is picked up to cause the operation of the switch machine SM to a normal position by the energization of a circuit closed from including front contact l of relay L, front contact 62 of relay N, and upper winding of relay WZZ, to The lock relay LS is maintained picked up as long as the track switch TS is out of correspondence with the controls selected because the reverse correspondence relay RCR is dropped away by the picking up of relay N and the dropping away of that relay closes a stick circuit which has been described for relay LS at back contact 43.

When the track switch TS has completed its operation to a normal locked position relay NCR is picked up by the energization of a circuit which has been described, and the picking up of that relay causes relay LS to be dropped away by the opening of the stick circuit for that relay at back contact 43 and the dropping away of relay LS deenergizes the switch machine control circuit and closes a circuit for the signal control relay BG, from including front contact 94 of relay CXR, back contact 49 of relay LS, back contact 59 of relay RCR, front contact 63 of relay NCR, back contact 64 of relay BXR, front contact 65 of relay BI-IR, polar contact 66 of relay BNR. in a right hand position, front contact 61 of relay BNR, and winding of relay BG, to The picking up of relay BG causes the red lamp in signal B to be extinguished by the opening of back contact 63 and it causes the green lamp in signal B to be steadily energized by a circuit closed from including front contact 69 of relay BHR, front contact of relay BG, and the green lamp in signal B, to

It is assumed that the normal direction of traffic through the track layout is to the right, and signal B is a higher speed signal than signals A and C, thus, the green lamp in signal B can be steadily energized only when track section T and T1 are unoccupied, while the signals A and C can be cleared as long as the track section immediately in advance of such signals is unoccupied.

Upon passage of a train over the route established from signal B to signal C the parts of the system associated with the establishment of that route are restored to normal in a manner very similar to that which has been described in connection with the restoration of the route establishing means associated with the route from signal A to signal C.

It will be noted in the circuit described'dbove for the energization of relay BG that such circuit requires front contact 65 of relay BHR. be closed, thus providing that track sections T and 2T in advance of signal B must be unoccupied before signal B can be cleared. If one of those track sections is occupied by a train at the time when an operator desires to establish a route from signal B to signal C a low speed call-0n signal can be cleared for signal B if the operator designates the entrance end of that route by the rotation of the button BNB in a clockwise direction and thus causes the picking up of relay BNR with its polar contacts operated to a left hand position. When a route is established from signal B to signal C and the relay BNR is picked up with its polar contacts operated to a left hand position, the relay BG can be picked up, irrespective of the position of relay BHR by the energization of a circuit closed from including front contact 94 of relay CXR, back contact 49 of relay LS, back contact 50 of relay RCR, front contact 63 of relay NOR, back contact 64 of relay BXR, polar contact 66 of relay BNR in a left hand position, front contact 61 of relay BNR, and winding of relay BG, to The picking up of relay BG due to such energization causes the steady energization of the green lamp in signal B by th energization of a circuit which has been described if the track sections T and ET are unoccupied by a train, and if either of those track sections are occupied, relay BHR is dropped away and the green lamp in signal B is energized with energy frequently interrupted by the coder CD by the energization of a circuit closed from including contact H of coder CD back contact 69 of relay BHR, front contact 70 of relay BG, and the green lamp in signal B, to

It is believed from the organization of the circuits which have just been described, it will be readily apparent that the establishment of a route from signal B to signal C can be effected when the entrance and exit ends of such route are designated and the entrance end is designated by the depression of button BNB, if there is no conflicting route established, and if track section T is unoccupied by a train, such being true because relay BNR can be picked up responsive to the depression of the entrance button BNB only when the track relay TR is energized. If track section ET is occupied by a train at the time when a route is established in the manner just described, the signal B will be cleared only after relay BHR has been picked up to close the pickup circuit for the signal control relay BG.

If, however, an operator designates the entrance and exit ends of an available route from signal B to signal C, designating the entrance end of such route by the rotation of the button BNB in a clockwise direction, the route can be established immediately, if there is no conflicting route established, irrespective of the occupied condition of track sections T and 2T, and relay BG will be picked up to cause the green lamp in signal B to be illuminated with steady energy if both track sections T and 2T are unoccupied by a train, or to be energized with pulsating energy if either or both of such track sections are occupied.

Indications at the control ofiice.-In order that an operator can be informed as to certain conditions existing in the field, suitable switch, track and signal indications are provided on the control panel at the control office. Although different means can be provided for the display of the various indications, in this embodiment of the present invention, the position of the track switch TS is indicated by a magnetically operated miniature switch point indicator TSK (see Fig. 1A) which is governed in accordance with the position of the polar contacts of a switch indicator relay WK. Relay WK maintains its polar contacts in correspondence with the switch control relay WZZ in the field, and it is picked up only when both of the correspondence relays for that track switch are dropped away. Thus the picked up position of the relay WK causes the energization of an indicator lamp CE for that track switch to provide an out-of-correspondence indication.

To consider as an example of how the switch point indicator TSK is positioned in accordance with the operation of the track switch TS, assume that the track switch TS is caused to be operated from its normal to its reverse position. As soon as the reverse position of the track switch is called for, the relay NOR is dropped away, and the relay WK at the control oiiice becomes energized upon the closing of a circuit from (13-), including polar contact 92 of relay WZZ in a left hand position (see Fig. 13), back contact 8d of relay RCR, back contact 85 of relay NCR, wire 19, and winding of relay WK, to (CN). The picking up of relay WK causes the illumination of the out-of-correspondence lamp CE by the energization of an obvious circuit closed at front contact 86, and the shifting of the polar contacts of relay WK in accordance with the polarity of energization of that relay causes the switch point indicator TSK to be operated to a reverse position in accordance with the energization of its reverse winding by a circuit closed from including polar contact 87 of relay WK in a right hand position, and winding R of switch point indicator TSK, to When the track switch has completed its operation to its reverse position, the relay RCR is picked up, and the circuit for relay WK is opened in the field at back contact 84 (see Fig. 1B). Relay WK in dropping away causes the lamp CE to be extinguished by the opening of front contact 86.

Track occupancy and switch lock indications are provided at the control ofiice in accordance with the condition of the polar neutral relay L'IK which is governed over a line circuit extending to the track layout. Such relay is energized with one polarity when the track section '1 is unoccupied by a train and the track switch TS is looked either normal or reverse, and such relay is energized with the opposite polarity when the track section T becomes occupied. Thus, at the control office, the lock indicator lamp LE is illuminated whenever the relay LTK is picked up, and the track indicator lamp is illuminated whenever the relay L'IK is picked up with its polar contacts operated to a left hand position in accordance with the dropped away position of the track relay TB in the field.

As an example of how such indications are provided, assume that an operator sets up a route as has been described from signal 13 to signal C- The picking up of relay N (see Fig. 1B) in the establishment of that route causes the relay LTK (see Fig. 1A) at the control ofiice to be energized by a circuit closed from (B-) including front contact 88 of relay N (see Fig. 1B), front contact 89 of relay TR, wire 18, and Winding of relay LTK, to (CN). The picking up of relay LTK causes the illumination of the lock lamp L by the closing of an obvious circuit at front contact at, but the lamp TE remains dark until a train enters the route to cause the track relay TR to be dropped away, because the relay LTK is ener gized with a polarity to operate its polar contacts to a right hand position. The dropping of relay TR causes relay LTK to be energized with a polarity to cause its polar contacts to be operated to a left hand position by a circuit closed from (3+), including back contact 39 of relay TR (see Fig. 1B), wire 78, and winding of relay LTK, to (CN). The lamp TE then beco s energized when a circuit is closed from including front contact 89 of relay LTK, polar contact 9| of relay LTK in a left hand position, and lamp TE, to When the track section becomes unoccupied, the relay LTK becomes energized with a polarity to cause its polar contacts to operate to a right hand position if the route is maintained established, and extinguish the lamp TE by opening its circuit at polar contact 9|. If restoration for the route has been effective the relay LTK is dropped away and indicator lamps TE and LE are both extinguished because of the opening of front contact (see Fig. 1A).

An indication is provided at the control ofiice Whenever an entrance relay NR in the field is picked up by the illumination of the indicator lamp GE included in the corresponding entrance button at the control oflice. Such indicator lamp is illuminated with pulsating energy whenever the entrance relay NR for that entrance point is picked up, but the signal for that point has not yet been cleared, and such indicator lamp be comes steadily energized as soon as that entering signal has been cleared. It is to be understood that other distinctive indications such as those provided by use of different colored lamps can as well be used.

As a specific example of how such indications are provided for each indicator lamp included within each entrance button, assume that an operator causes the picking up of entrance relay BNR for the establishment of a route from signal B to signal C. Upon designation of the entrance point at signal 13 by the actuation of entrance button BNB, the picking up of relay BNR causes the picking up of relay BGK at the control office by the energization of a circuit closed from (18+), including front contact 33 of relay BNR (see Fig. 10), back contact 32 of relay BG, wire 3!, contact 39 of button BXB closed in a normal position, and Winding of relay BGK, to (ON). The picking up of relay BGK due to such energization causes its polar contacts to be operated to a left hand position to close a circuit for the energization of lamp BGE with pulsating energy supplied by the coder CD from including contact '12 of coder CD, polar contact 33 of relay BGK in a left hand position, front contact M of relay BGK, and lamp BGE, to After the route from signal B to signal C has become completely established and signal B is cleared in accordance with the picking up of relay BG, relay BGK is energized with a polarity to cause its polar contacts to be actuated to a right hand position by a circuit closed from (l 3), including resistance '16, front contact 32 of relay BG, wire 3|, contact at of button BXB closed in a normal position, and winding of relay BGK, to (CN). The energization of relay BGK with such polarity causes an obvious circuit to be closed at polar contact 73 of relay BGK in a right hand position to effect the steady energization of relay BGE as long as signal B at the track layout is clear. Resistance i5 is a limiting resistance comparatively low in value to the resistance of the winding of relay BGK and is used to limit the flow of current ii an operator should inadvertently depress button BXB when signal B is clear.

From the typical conditions which have been described, and upon reference to the accompanying drawings, it will be apparent that one line wire is required extending from the control office to the track layout for governing each entrance relay, and one line wire is required extending from the control office to the track layout for picking up each exit relay, the line wire for the control of the exit relay being also used for the communication of signal and entrance indications. In addition to such line wires a common line wire (not shown) is provided for connecting the terminals (CN) of the control office and field batteries.

Having described the present invention as applied to the control of a simple track layout as one embodiment, it is desired tobe understood that this form is selected to facilitate and simplify the disclosure of the present invention rather than to limit the number of forms that the present invention may assume; and it is to be further understood that various modifications, adaptations and alterations may be applied to the specific form shown to meet the requirements of practice, without in any manner departing from the spirit or scope of the present invention except as limited by the appending claims.

What we claim is:

1. In a switch and signal control system of the character described for governing from a control oihce the power operation of each track switch required for setting up each of a plurality of conflicting routes extending through a distant track layout between entrance and exit points; an entrance and an exit button at the control ofiice for the respective entrance and exit points to a given one of the routes for a given direction of traffic, said entrance button having a first operated position in which it remains until manually restored and a second operated position from which it is self-restored; a track section in advance of the entrance point to said given route; an entrance relay at the track layout for the entrance to said given route; a control line wire connecting said entrance button and said entrance relay; circuit means responsive to the actuation of said entrance button to said first operated position for energizing said entrance relay over said line wire, irrespective of the condition of occupancy of said track section; circuit means responsive to the actuation of said entrance button to said second operated position for energizing said entrance relay over said line wire, only if said track'section is unoccupied; stick circuit means at the track layout effective to maintain said entrance relay energized dependent for deenergization upon entrance of a train into said track section, only if the energization of that entrance relay has last been effected by the actuation of said entrance button to said second operated position; and route establishing means responsive to the actuation of said exit button jointly with the energization of said entrance relay for causing the power operation of each track switch required to set up a route between said entrance and exit points, such route establishing means being maintained effective dependent upon the energization of said entrance relay.

2. In a switch and signal control system, a remote track layout having a signal for governing trafiic thereover by giving a clear or stop indication and a call-on indication, a detector track section located in advance of said signal and provided with a track relay, a polar-neutral relay for governing the indications of said signal, circuit means for causing said signal to give a stop indication while said relay is deenergized and for giving said clear indication when said relay is energized with one polarity but causing said signal to give its call-on indication when said relay is energized with the opposite polarity, manually operable contact means having two distinctive operated positions, a control circuit for said relay having potential of one polarity or the other applied thereto by said manually operable contact means in one or the other of its distinctive positions respectively but said control circuit being effective to energize said relay when said one potential is applied only if said track relay is picked up and being efiective to energize said relay when the opposite potential is applied irrespective of the picked up condition of said track relay, and a stick circuit for said relay closed only when it is energized from said one potential and said track relay is picked up.

3. In a switch and signal control system of the character described for governing from a control office the power operation of each track switch required for setting up each of a plurality of conflicting routes extending through a remote track layout between entrance and exit points; an entrance button and an exit button at the control oflice for the respective entrance and exit points to a given one of the routes for a given direction of traffic, said entrance button having a first operated position in which it remains until manually restored and a second operated position from which it is self-restored; a signal having high and low speed indications for governing entrance to said given route; a track section in advance of said signal; an entrance relay at the track layout for the entrance to said given route; a line circuit connecting said entrance button and said entrance relay; circuit means responsive to the actuation of said entrance button to either said first or second operated position for energizing said entrance relay over said line circuit; stick circuit means eifective to maintain said entrance relay energized dependent for deenergization upon entrance of a train into said track section, only if the energization of that entrance relay has last been efiected dependent upon said entrance button in said second operated position; route establishing means responsive to the actuation of said exit button jointly with the energization of said entrance relay for causing the power operation of each track switch required to set up a route between said entrance and exit points; circuit means responsive to the establishment of said given route for clearing said signal by displaying said high speed indication only when said track section is unoccupied and only if said entrance relay has last been energized in accordance with the actuation of said entrance button to said second operated position; and circuit means responsive to the establishment of said given route for clearing said signal by displaying said low speed indication whenever said entrance relay has last been energized in accordance with the actuation of said entrance button to said first operated position and said track section is occupied by a train.

4. In a switch and signal control system, a track layout remote from a control ofiice, said track layout including at least one track switch for providing a plurality of difierent routes between signal locations constituting entrance and exit points, an entrance relay and an exit relay for each of said entrance and exit points located adjacent said track layout, route establishing means adjacent said track layout and responsive to the picking up of an entrance relay for one end of any given route and the picking up of an exit relay for the opposite end of that route for governing the power operation of the track switch to set up that route and clear the signal at the end having its entrance relay picked up. a control line wire for each of said entrance and exit relays for the several entrance and exit points extending between said control ofiice and said track layout, manually operable contact means at the control office for each of said entrance and exit points operable to define the corresponding point as the entrance or the exit end of a route, circuit means associated with each of said manually operable contact means efiective to energize said entrance relay for the corresponding point over its control line wire when that manually operable contact means is operated to define such point as the entrance end of a route and to energize the exit relay for the corresponding point over its control line wire when said manually operable contact means is operated to define that point as the exit end of a route, a signal indication relay at the control oflice for each of said entrance and exit points, said relay being normally connected to the line circuit extending to the exit relay for the corresponding point, and circuit means at the track layout associated with each of said-signals and efiective to disconnect the exit relay for the corresponding point from its control line wire and to energize such line wire when the signal at that point is in a clear condition whereby the corresponding signal indication relay in the control ofiice is energized.

5. In a switch and signal control system, a remote track layout having at least one power operated track switch for setting up different routes between signal locations constituting entrance and exit points, an entrance control line circuit and an exit control line circuit for each of said signal locations extending to a control ofiice, manually operable entrance and exit buttons located on a miniature track diagram at said control office at points corresponding to said sig nal locations, circuit means responsive to the actuation of an entrance button for energizing the corresponding entrance control line circuit, circuit means responsive to the actuation of an exit button for energizing the corresponding exit control line circuit, entrance and exit relays at the track layout associated with each of said signal locations and responsive to the energization of their respective entrance and exit control line circuits, route establishing means at the track layout rendered effective in response to the energization of an entrance relay and an exit relay for the signal locations at the opposite ends of any given route for causing the operation of said track switch to establish that route and for clearing the signal at the end of the route having its entrance relay energized, circuit means associated with each signal location for applying energy of one polarity to the exit control line circuit for that signal location when the associated entrance relay is picked up and the associated signal is at stop, and for applying the opposite polarity to such exit control line circuit when the corresponding signal is cleared, relay means at the control oflice for each of said signal locations, said relay means for each signal location being connected to the exit control line wire for that location only while the corresponding exit button is non-operated, and indication means associated with each signal location and controlled by the corresponding indication relay means to give one indication when that signal location is designated as an entrance point and to give another indication when the corresponding signal has been cleared in response to such designation.

6. In a switch and signal control system of the entrance-exit type for governing from a control ofiice the establishment of routes through a track layout having at least one track switch and having signal locations constituting entrance and exit points; entrance and exit control buttons at the control office for each of the signal locations, each of said entrance buttons having a call-0n operated position in which it remains until manually restored, and having signal clearing and signal-at-stop positions from which it is selfrestoring to a neutral position, and each of said exit buttons being of the self-restoring type; a polar-neutral entrance relay at the track layout for each signal location; a neutral exit relay at the track layout for each signal location; entrance and exit control line circuits extending from the control oflice to the track layout, there being one line circuit for each entrance and each exit relay; circuit means associated with each signal location and acting upon the actuation of the entrance button for that location to a call-on position to energize said entrance relay for that location over its line circuit with one polarity irrespective of the condition of occupancy of the track in advance ofsuch signal, and to energize said entrance relay with the opposite polarity when said entrance button is actuated to said signal clearing position only provided said trackway in advance of such signal is unoccupied, and to energize said entrance relay with said one polarity when said button is operated to said signal-at-stop position; circuit means associated with each signal location and acting upon the actuation of the exit button for that location to energize said exit relay for that location if it is the exit end of an available route having its entrance relay energized with either polarity; route establishing means at the track layout rendered eiTective in response to the energization of an entrance relay and an exit relay for the signal locations at the opposite ends of any given route for causing the operation of said track switch to establish that route; circuit means for clearing the signal at the entrance end of an established route, said means being efiective to clear a callon signal if said entrance relay is energized with one polarity, but to clear a high speed signal if siacl entrance relay is energized with the other polarity; and stick circuit means at the track layout for each of said entrance relays efiectively closed only when said entrance relay is initially energized with said other polarity and only when said track relay is energized, said stick circuit energizing said entrance relay with a polarity corresponding to said other polarity; whereby each signal may be a stick or a non-stick signal in accordance with the distinctive control of its associated entrance button, and whereby each signal may be restored to stop when it is used as a stick signal by momentarily energizing such relay in a direction opposite to the polarity of energy provided by said stick circuit.

'7. In a switch and signal control system, a remote track layout including at least one track switch for providing a plurality of different routes between signal locations constituting entrance and exit points, a detector track section associated with said track switch and provided with a track relay, route establishing means manually rendered active from a control office for. controlling the power operation of said track switch to establish any given route and clear the signal at the entrance thereto, circuit means eiiective while said track relay is deenergized for maintaining said route establishing means active independently of its manual control from said control office, a normally deenergized line circuit extending between the track layout and the control office, circuit means at the track layout for applying energy of one polarity to said line circuit when said route establishing means is rendered active to set up a route over said track switch providing said track relay is energized but applying energy of the opposite polarity whenever said track relay is deenergizeol, and normally inactive indication means at the control office including a neutral-polar relay responsive to the energization of said line circuit with said one polarity to display an indication that said track switch is included in a route by said route establishing means, said indication means being responsive to the energization of said line circuit with said opposite polarity to display the same said indication that said track switch is included in a route and also that its said detector track section is occupied by a train.

8. In a switch and signal control system of the entrance-exit type for setting up routes through a track layout remotely located from a control ofiice, signals for governing trafiic in both directions over each of the routes, entrance and exit buttons at the control ofiice for each of the signal locations, an entrance relay and an exit relay at the track layout for each of the signal locations, a control line wire extending from the control oflice to the track layout for each respective entrance and exit relay, circuit means responsive to the actuation of the entrance button for any given signal location for energizing the entrance relay for that location over its said entrance control line wire, circuit means responsive to the actuation of the exit button for any given signal location for energizing the exit relay for that signal location over its said exit control line wire, route establishing means responsive to the picking up of an entrance relay and an exit relay for the opposite ends of any given route for setting up that route and for clearing the signal at the entrance end when such route has been set up, normally deenergized indication relay means at the control ofiice associated with each signal location and connected to the exit control line wire for the corresponding signal only while the exit button for that signal is non-operated, circuit means at the track layout associated with each signal for disconnecting the exit relay from its said control line wire and applying energy of one character when the entrance relay for that signal is picked up and for applying energy of a different character when the associated signal is cleared, and an indication lamp at the control oflice associated with each of the entrance buttons and controlled by the corresponding indication relay means to give a flashing indication when said indication relay means is energized with current of said one character and to cause said lamp to give a steady indication when said indication relay means is energized by current of said different character.

ANDREW LANGDON. WALTRUS L. LIVINGSTON. 

